'\" te
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.TH AIOCANCEL 3C "Feb 5, 1997"
.SH NAME
aiocancel \- cancel an asynchronous operation
.SH SYNOPSIS
.LP
.nf
#include <sys/asynch.h>

\fBint\fR \fBaiocancel\fR(\fBaio_result_t *\fR\fIresultp\fR);
.fi

.SH DESCRIPTION
.sp
.LP
\fBaiocancel()\fR cancels the asynchronous operation associated with the result
buffer pointed to by \fIresultp\fR. It may not be possible to immediately
cancel an operation which is in progress and in this case, \fBaiocancel()\fR
will not wait to cancel it.
.sp
.LP
Upon successful completion, \fBaiocancel()\fR returns  \fB0\fR and the
requested operation is cancelled.  The application will not receive the
\fBSIGIO\fR completion signal for an asynchronous operation that is
successfully cancelled.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, \fBaiocancel()\fR returns \fB0\fR. Upon failure,
\fBaiocancel()\fR returns \fB\(mi1\fR and sets \fBerrno\fR to indicate the
error.
.SH ERRORS
.sp
.LP
\fBaiocancel()\fR will fail if any of the following are true:
.sp
.ne 2
.na
\fB\fBEACCES\fR\fR
.ad
.RS 10n
The parameter \fIresultp\fR does not correspond to any outstanding asynchronous
operation, although there is at least one currently outstanding.
.RE

.sp
.ne 2
.na
\fB\fBEFAULT\fR\fR
.ad
.RS 10n
\fIresultp\fR points to an address outside the address space of the requesting
process.  See \fBNOTES\fR.
.RE

.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 10n
There are not any outstanding requests to cancel.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
MT-Level	Safe
.TE

.SH SEE ALSO
.sp
.LP
.BR aioread (3C),
.BR aiowait (3C),
.BR attributes (7)
.SH NOTES
.sp
.LP
Passing an illegal address as \fIresultp\fR will result in setting \fBerrno\fR
to \fBEFAULT\fR \fIonly\fR if it is detected by the application process.
